JP2518409Y2 - Needle plate of double chain stitch sewing machine - Google Patents

Description

[Detailed Description of the Invention] Industrial field of application The present invention has a double loop stitch looper thread appearing on the back side of a cloth, as shown in FIG. The present invention relates to a needle plate of a double chain stitch sewing machine capable of being obtained.

The prior art double loop seam appears on the back side of the fabric with the looper thread in three layers and the needle thread wrapping the looper thread for each stitch. Different depending on the balance of thread tension between the needle thread and the looper thread. An example is shown in FIGS. 5 and 6, of which, as shown in FIG. 5, the one in which the looper thread is opened in three and the seam looks round and soft is called a balloon stitch, It is used for knitted fabrics with a high degree of elongation and for those with a favorable texture, and as shown in Fig. 6, looper yarns that look like a rope and consist of two yarns are hard and less stretchable fabrics. in use.

Problems to be solved by the invention When the tension of the needle thread is increased and the seam is tightly tightened, the looper thread is opened in three, and a balloon stitch can be formed. However, increasing the tension of the needle thread is This reduces the amount of needle thread supplied to the cloth, which causes a wavy phenomenon called puckering in the sewn product. Conversely, even if the tension of the looper thread is made weaker than that of the needle thread, the tension of the looper thread is originally set to a low tension, which is a fraction of the needle thread. However, there was a problem such as causing sewing defects such as skipped stitches.

An object of the present invention is to obtain a double chain seam having a good texture in which looper threads are opened in three, that is, a balloon stitch without causing puckering.

Therefore, according to the present invention, a sewing machine needle that moves vertically through a needle hole provided in a needle plate and a looper thread are passed through the needle plate and reciprocates in a direction orthogonal to the cloth feeding direction below the needle plate. In a double chain stitch sewing machine including a looper, a recessed portion that is wider than the needle hole and protrudes toward the looper base side from the needle hole is formed subsequent to the rear portion of the needle hole, and the looper thread is accommodated in the recessed portion. It is characterized by doing so.

The double chainstitch sewing machine referred to here includes a sewing machine that only performs double chainstitching, as well as a double chainstitch and a safety stitch sewing machine that performs edge stitching.

The cloth targeted by the present invention may be of any type, from thick cloth such as denim to cutter shirts and other thin cloth.

Action When forming a double chain stitch, as shown in FIG. 4, the looper 1 reaches the right dead center and is inverted, and when going left, the tension of the looper thread 2 becomes 0, and the tip of the looper and the one stitch before The looper thread 2 is loosened between the interlacing points A of the needle thread 3.
Then, the tension of the needle thread causes a bulge. This bulge is oriented vertically in the conventional needle plate. In particular, when the needle for double chain stitches is inclined like the needle for edge stitching and the needle hole is a long hole, as in the case of a safety sewing machine, face the long hole direction and finish sewing. As shown in FIG. 6, the appearance afterward becomes a rope shape in which threads are vertically stacked.

In contrast, the width behind the needle hole is wider than the needle hole,
Further, when the concave portion projecting from the needle hole to the looper base side is formed, when the slack of the above-mentioned thread is tightened with the needle thread, the needle thread spreads laterally and is accommodated in the concave portion, and after sewing, as shown in FIG. It looks like.

Embodiment FIG. 1 shows a needle plate of a safety stitch sewing machine, and the needle plate 4 is provided with a needle hole 5 for edge stitching and a needle hole 6 for double chain stitch, As shown in detail in FIGS. 2, 3, and 7, the double chain stitch needle hole 6 is wider than the needle hole 6 behind the needle drop 8 by 2 to 5 stitches. Further, it has a concave portion 7 that projects to the left side (looper base side) from the needle hole 6.

In the above embodiment, the recess 7 has a bottomed shape, but it may be a through hole corresponding to the needle hole 6. Further, one side of the concave portion 7 may be formed so as to be substantially orthogonal to the needle hole 6, or may be curved or inclined, but as shown in the figure, it is preferably bottomed and between the needle hole 6 and It is desirable to form the constricted portion 9 so that the bulge of the looper thread can be surely settled in the concave portion.

Although the above embodiment shows the needle plate of the safety stitch sewing machine, in the embodiment relating to the needle plate of the double chain stitch sewing machine in which the needle vertically moves, the rear end of the recess for receiving the loop is
It is formed by extending 2 to 5 stitches backward from the needle drop.

Experimental Example Using the needle plate of the above example having needle holes of the sizes shown in the table below and a conventional needle plate having no recesses, denim fabric was used with a # 20 cotton thread, and the stitch pitch was 8 / inch. When sewing with a stitch length of 0.32 cm, in order to obtain a stitch with an open looper thread as shown in Fig. 5, the conventional needle thread tension must be 100 g and While some waving phenomenon was observed in the product, in the above embodiment, even if the needle thread tension was 60 g, the looper thread was sufficiently opened and a soft and textured seam was obtained. I couldn't see it.

Effect of the Invention According to the needle plate of the present invention, as described above, the loop of the double loop seam falls sideways (looper base side) and is housed in the recessed portion, and the looper thread is generated without causing puckering. You can get a double chain seam that is soft enough to open, yet rounded and full of texture.

[Brief description of drawings]

1 is a plan view of the needle plate of the safety stitch machine, and FIG.
FIG. 3 is an enlarged view of a main part of the drawing, FIG. 3 is a sectional view taken along the line II of FIG. 2, FIG. 4 is a view showing a state when a double chain stitch is formed, and FIGS. 5 and 6 are safety stitch sewing machines. Fig. 5 shows an example of a balloon stitch in which a looper thread is opened, and Fig. 6 shows an example of a rope-shaped stitch when the seam formed by is viewed from the back side.
FIG. 7 is a sectional perspective view taken along the line I-I of FIG. 1 ... Looper, 2 ... Looper thread, 3 ... Needle thread, 4 ... Needle plate, 6 ... Needle hole, 7 ... Recess, 8 ... Needle drop

Claims (1)

(57) [Scope of utility model registration request] 1. A needle, which moves up and down through a needle hole provided in a needle plate, and a looper, through which a looper thread is passed, and which reciprocates in a direction orthogonal to the cloth feeding direction below the needle plate. In the double chain stitch sewing machine, a recessed portion that is wider than the needle hole and protrudes toward the looper base side from the needle hole is formed subsequent to the rear portion of the needle hole, and the looper thread is accommodated in the recessed portion. The needle plate of the characteristic double chain stitch sewing machine.